Temperature Field Analysis And Cooling Structure Design Of Permanent Magnet Synchronous Motors

With the characteristics of high power density and high efficiency,permanent magnet synchronous machine(PMSM)is widely used both in production and in our daily life.In recent years,as the advancement of technology and iteration of products,the requirement of the power density of PMSM is continuously getting higher and higher.High power density can lead to the improvement of performance but also bring about high temperature rise,which threatens the functioning and the life span of the electric machine.Thus,the research of the temperature field distribution and cooling system strategy is of great significance to solve the over-heating problem of PMSM.This paper studies a water-cooled PMSM.Computational Fluid Dynamics(CFD)simulation is employed to analyze the 3D temperature field of the machine.Cooling effects and temperature distribution of the machine,pressure drop and consumption of water pump with four different cooling structures,i.e.spiral,radial,axial-zigzag and radial-zigzag channels are analyzed and compared.With identical length and cross-sectional area,axial-zigzag channel structure is proved to be the optimal choice in terms of cooling effects.Different structures and parameters of axial-zigzag channel are analyzed to obtain the optimal design.To further explore the possibility of cooling structure design,spoilers are added to the axial-zigzag channel and the usage of spoiler is proved to be an effective way to improve the cooling effects.A water-cooled PMSM model machine is created and by comparing calculation results and the experimental data,the feasibility of the cooling design and the accuracy of simulation are confirmed.The main arrangement of this thesis is summarized as following:1.The background and progress of the research on temperature field analysis and cooling structure design of electric machine are introduced in the first chapter.2.Based on heat transfer theory,principles of fluid dynamics and the calculation method employed by Computational Fluid Dynamics(CFD)simulation,the 3D temperature field of a water-cooled PMSM is established and analyzed using CFD simulation method.3.With the analysis of 3D temperature field of PMSM,cooling effects of the machine and consumption of water pump with four different cooling structures,i.e.spiral,radial,axial-zigzag and radial-zigzag channels are analyzed and compared.Axial-zigzag channel structure is proved to be the optimal choice in terms of cooling effects.However,the power of water pump which it requires is the highest.4.Cooling effects with different structures and parameters of axial-zigzag channel structure are analyzed to obtain the most adequate design.The addition of spoilers to axial-zigzag water channel can bring about positive influence on the improvement of the cooling efficiency.The influence of size and the configuration of spoilers are studied using CFD simulation.A real model PMSM is made.By comparing the simulation results and experimental data,the feasibility of the design and the accuracy of the simulation are confirmed.